1. Field of the Invention
The invention relates to an apparatus in the form of a concrete conveying device for conveying fluent material.
2. Description of the Related Prior Art
Such distribution devices are known (EP 432 854 and WO 00/24988). They are provided with a telescopic boom section that is pivotally jointed to a slewing track ring for the distributor and by means of a hydraulic cylinder unit can be swiveled from a horizontal transport or rest position up to a substantially vertical working position. By means of this slewing track ring the distribution boom is mounted on an appropriate transport vehicle, possibly a motor lorry or crane truck. These distribution booms serve to carry conduits, especially for the conveyance of concrete, and are used for the most part for the distribution of concrete for the production of ceiling slabs of buildings and the like. To this end the concrete-conveyance conduit is carried by the telescopic section of the distribution boom and therefore must be adjustable with respect to the boom as it is extended. For this purpose there are known scissor-type conveyance conduits made up of swiveling elements connected to each other by means of articulated joints. When the telescopic section of the boom is extended, these conduit elements are swiveled in the manner of scissors, so that the conveyance-conduit elements with their articulated joints move past each other, after which the conveyance conduit can follow the telescopic movement.
In the case of the distribution device in accordance with EP 432 854 B1 both the relatively immobile section of the telescopic and the section that moves relative thereto are provided with a reinforcement beam to which are attached, respectively, the part of the concrete-conveyance conduit that leads to the telescope and the part that leads away from it. This leads to a comparatively large, heavy and space-consuming structure. The telescopic section of the boom and the extensible part of the telescope, which carries the follow-up sections of the conveyance conduit, becomes subject to considerable forces, especially when high pumping pressures occur during operation or on the occasion of substantial pumping strokes when the pumping head changes. Accordingly, such heavy loads call for an appropriately massive construction of the telescope. In the case of the distribution boom in accordance with WO 00/24988, on the other hand, the articulated concrete-conveyance conduit is attached to the telescopic section of the boom by means of bearing blocks and this again places significant loads to be considered in the design of the side of the boom.